Method for assembling slats of venetian blinds and mechanism for use in the exercise of the method

ABSTRACT

In the production of slat packages for Venetian blinds, the slats are placed over each other and introduced between a first and a second transverse band in double rungs in carrying bands or ladders including bands or cords. The slats are conveyed one by one to the carrying band and lifted after being introduced into a double rung to enable mechanical introduction of the slats between the double rungs. A double rung is stretched between two teeth projecting over the plane in which the slats are conveyed. A slat is conveyed forward until it has passed under the first of the two transverse bands, and the slat is then lifted so that when further conveyed it passes over the second of the two transverse bands. The slat can be lifted by an inclined plane placed between the teeth.

FIELD OF THE INVENTION

The present invention concerns a procedure for production of slatpackages for Venetian blinds whose slats, placed over each other, areintroduced between a first and a second transverse band in double rungsin carrying bands or ladders consisting of bands or cords, by whichprocedure the slats are conveyed one by one to the carrying band andlifted after being introduced into a double rung of the carrying band orladder.

1. Background of the Invention

It is possible in order to ensure that the slats of a Venetian blindcannot turn round in the carrying bands to use carrying bands with twotransverse bands in each rung, between which the slats are introduced.In principle, the introduction can take place in two ways, either byeach slat being introduced directly between the two bands in each rungor by each slat being introduced after the two bands have been crossedin such a way that the lower band lies over the slat and the upper bandlies under the slat.

2. Description of the Prior Art

From DE patent paper 2,003,304 a procedure is known where a carryingband with double ladder rungs is stretched between two rotary discshaving recesses placed in the periphery. The distance between twosuccessive pairs of recesses corresponds to the distance between twosuccessive double rungs of the carrying ladder. Before a slat isintroduced between the two bands of a rung, the bands are separated bymeans of special spreading devices, which are then placed in theconveying path of the slat. After the slat has been introduced, thespreading devices must be moved away from this conveying path. The knownprocedure thus requires a comparatively complicated equipment. Besides,it is not possible by the known procedure to introduce a slat into arung whose transverse bands are twisted.

SUMMARY OF THE INVENTION

The purpose of the invention is to present a procedure which makesintroduction of the slats by means of a simple and safe equipmentpossible. Furthermore, it must be possible to introduce the slatsbetween twisted transverse bands.

This is achieved according to the invention in such a way that a doublerung of ladder is stretched between two teeth projecting over the planein which the slats are conveyed, that a slat is conveyed until it haspassed under the first of the two transverse bands, and that the slat isthen lifted so that when further conveyed it passes over the second ofthe two transverse bands.

The presented procedure can immediately be mechanized by means of anappropriate mechanism which moves and stretches the carrying band.

It is desirable that the slat, after being conveyed until it has passedunder the first of the two transverse bands, is lifted by means of aninclined plane placed between the teeth. Hereby correct lifting of theslat is ensured in a very simple way.

It should be noted that the double rung can be stretched between the twoteeth with the end of the carrying band that is uppermost in thefinished slat package turning either towards or away from the conveyedslat. In the first case the slat will be introduced immediately betweenthe two transverse bands. In the second case the slat will be introducedbetween twisted transverse bands.

As previously mentioned, the invention also concerns a mechanism for usein the exercise of the procedure and comprising protruding teeth betweenwhich a double rung of ladder can be stretched. According to theinvention this mechanism comprises a rotary roller with pairs of teethplaced on the periphery, and where the distance between two successivepairs of teeth corresponds to the distance between two successive doublerungs of a carrying ladder. The roller is turned a tooth every time anintroduced slat is lifted free of the mechanism, so that the succeedingdouble rung is in the right place for the introduction of the succeedingslat.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be explained in more detail inconnection with the drawing, where

FIG. 1 is a schematic presentation of a carrying band for a Venetianblind with slats introduced between double rungs,

FIG. 2 shows the same, but with slats introduced between twistedtransverse bands,

FIGS. 3-5 introduction of a slat into a double rung, schematically andseen from the side,

FIG. 6 in perspective a mechanism for use in connection withintroduction of slats between twisted double transverse bands in a rungand a slat immediately before the introduction,

FIG. 7 the same after the slat has been introduced,

FIG. 8 in perspective a part of a slat packing machine with a mechanismaccording to FIGS. 6 and 7, and

FIG. 9 the mechanism shown in FIG. 6, but for use in connection withintroduction of slats immediately between the two transverse bands in arung.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2 show in schematic form carrying bands with double rungs ofladder 2,2' and the Venetian blind slat 3, which has been introducedinto a rung directly between its two transverse bands and betweentwisted transverse bands, respectively. The double rungs ensure that theslats cannot turn round in the carrying band.

It appears from FIGS. 3-5 how slats 3 can be introduced mechanically oneby one between the two transverse bands in a rung. A double rung 2,2' isstretched in such a way that the two transverse bands 2 and 2' areseparated between two teeth 4 projecting over the plane in which theslat is being conveyed, see also FIGS 6-9. The slat 3 is moved forwarduntil it has passed under the first of the two transverse bands 2 (FIG.4). After that the slat is lifted, in the embodiment shown here by meansof one or more inclined planes 5 placed between the teeth, so that whenmoved further forward the slat passes over the second of the twotransverse bands 2'. After that the slats are lifted in an actuallyknown way (FIG. 8) so that a succeeding slat can be introduced. Untilthat is done, the succeeding double rung is stretched between either thetwo above-mentioned teeth or between the succeeding teeth in a mechanismas shown in FIGS. 6-9.

The shown mechanism comprises a rotary roller with pairs of teeth placedon the periphery. The distance between two succeeding pairs of teethcorresponds to the distance between two succeeding double rungs. Theroller is moved synchronously with the forward movement of the slats, sothat the next rung of the ladder is in the right place when the nextslat is moved forward.

If the roller is turned as indicated by the arrow in FIG. 6, (in aclockwise direction) the introduction of the slats shown in FIG. 2 isachieved by introducing slat 3 under trailing band 2' and then overleading band 2 to form the twisted bands of FIG. 2. If the roller isturned as indicated by the arrow in FIG. 9 (in a clockwise direction),the introduction of the slats shown in FIG. 1 by introducing slat 3under trailing band 2 and then over trailing band 2' to form thenon-twisted transverse bands of FIG. 1 is acheived.

What is claimed is:
 1. An apparatus for inserting slats for Venetianblinds between pairs of transverse bands in carrying bands or laddersincluding bands or cords, said apparatus comprising:a rotary rollerhaving transversely arranged pairs of teeth projecting from a peripherythereof for entraining the carrying bonds or ladders about a peripheryof the rotary roller, a distance between two succeeding pairs of teethcorresponding to a distance between two succeeding pairs of transversebands in a carrying band or ladder for separating the two transversebands of a pair of transverse bands by said pair of teeth, conveyingmeans for conveying the slats one by one to an insertion zone at theroller in a first conveying plane so that a slat is first passed underone of the transverse bands of said pair of transverse bands, liftedinto a second conveying plane above the first conveying plane, and thenpassed over the other transverse band of said pair of transverse bands,lifting means for carrying the inserted slats away from the insertionzone, and an inclined plane located on said rotary roller between eachpair of the transversely arranged teeth, said inclined plane lifting theslats from the first conveying plane to the second conveying plane. 2.An apparatus according to claim 1, wherein the roller is rotatable ineither direction.
 3. An apparatus according to claim 2, wherein saidcarrying band or ladder is supplied from below said roller and removedfrom above said roller so that when the transverse bands of saidcarrying band or ladder are in engagement with said pairs of teeth onthe periphery of said roller, rotating in an upward direction, then thedirection of rotation of the roller determines whether the slats, whichare being conveyed to the insertion zone from one and the same directionalong the conveying plane, are inserted between twisted or non-twisted,respectively, transverse bands of the carrying band or ladder.